On-Grid Inverter converts DC power to AC power for feeding back to the grid. The frequency of the output voltage of the grid-connected inverter needs to be the same as the grid frequency (50 or 60Hz), which is generally achieved by the oscillator in the machine, and the output voltage will also be limited not to exceed the grid voltage. Modern high-quality grid-connected inverters can have an output power factor of 1, which means that the output voltage and current phases are the same, and the phase difference between them and the grid voltage is within 1 degree. There is a microprocessor in the inverter that can sense the AC waveform of the grid, and according to this waveform, generate voltage and send it back to the grid. However, the electricity sent back to the grid needs to have a certain proportion of reactive power, so that the power of the nearby grid is within the allowable limit. noon) its voltage may rise too high. on grid solar inverter, micro inverter on grid, 25 kw on grid inverter, on grid power inverter, 15kw on grid inverter Ningbo Autrends International Trade Co., Ltd. , https://www.aitsolarpanels.com
Recently, China Mobile said it will build the world's largest LTE network. In 2013, China Mobile’s 4G network coverage will exceed 100 cities, 4G terminal procurement will exceed 1 million, the number of base stations will exceed 200,000, and the coverage population will exceed 500 million.
It is understood that China Mobile has built a TD-LTE trial network in 15 cities in 2012 and has achieved full coverage of major urban areas in Hangzhou, Shenzhen, and Guangzhou, and has also conducted various forms of large-scale TD-LTE customer experience activities. China Mobile staff stated that the TD-LTE technology and industry have matured and have the basis and conditions for scale development. China Mobile will expand the scale of its pilot network.
At the same time, China Unicom and China Telecom are secretly making efforts. If 4G is licensed in the second half of 2013, China Unicom and China Telecom will inevitably increase their investment in 4G. The development of 4G has become an irresistible trend. Regardless of whether it is for operators or equipment manufacturers, its impact will be enormous.
4G development prospects are optimistic
At present, there are 29 operators in the world have built 64 TD-LTE-Advanced trial networks, a 4G standard led by China. Among them, 13 operators have opened 14 commercial networks, and TD-LTE is expected to be implemented globally. More large-scale commercial applications.
Zhao Yuhai, Director of the Department of High-tech Development and Industrialization of the Ministry of Science and Technology, said that in the past 20 years, China’s mobile communication technologies and industries have achieved remarkable achievements. In particular, TD-LTE has become one of the international 4G mainstream standards in 2012, and China has achieved mobile. From the catch-up to the leap-forward development of communication technology, Chinese enterprises represented by Huawei and ZTE have formed the industrial chain of mobile communication equipment and systems, and their global market share ranks among the top in the world.
Talking about the future development of 4G, Zhao Yuhai revealed that the Ministry of Science and Technology is working with other departments to jointly promote the development and industrialization of TD-LTE and 4G mobile communication evolution technologies. In addition to strengthening linkages between relevant technology plans, related departments will also strengthen the research and development of key technologies, focusing on breakthroughs in smart terminal chips, operating systems, new human-computer interactions, low-power key technologies, and new application software. At the same time, combining the development of the mobile Internet, Internet of Things, cloud computing, big data, smart cities, and smart homes, it will promote the innovative application of broadband mobile communications.
Chairman of China Mobile Kuang Guohua is full of confidence in the development of 4G. He said: "This year is a crucial period for the development of TD-LTE. China Mobile firmly believes that TD-LTE technology and industry have matured and have the conditions for scale development. In 2013, TD-LTE terminals that China Mobile will purchase include not only MiFi and other data types. The terminal also includes a variety of TD-LTE smart phones.With the rapid development of TD-LTE, it is expected that TD-LTE terminals will gradually reach the level of 3G terminals in the next two years. Not only will there be multiple high-end mobile phones, but also mid-to-low end devices. Mobile phones enter the market, providing consumers with a wealth of choices and improved services."
According to Shu Yan, deputy general manager of CCID Consulting's Communications Industry Research Center, the market needs a familiar process for 4G. China Mobile took the lead in this step, at least in the 4G market. Zero Consulting IT Telecom Director Zeng Jun is more cautious. He believes that 4G is like an 8-core mobile phone. The ecosystems such as terminals, applications, and user habits are not yet mature. Even if the Ministry of Industry and Information Technology issues 4G licenses this year, it is impossible. There is any one operator that will formally commercialize 4G services this year, and it will be possible to realize it as soon as possible in 2014.
China Mobile is not alone
The industry believes that from the perspective of the relationship between input and output of 4G, investment in 4G is very large. Due to the frequency band, the number of base stations required far exceeds the current 3G, and huge investment costs need to be digested. This is also China. Telecom and China Unicom are not eager to launch the 4G.
However, no rush to launch does not mean that there is no action.
Wang Xiaochu, chairman of China Telecom, once disclosed: "China Telecom has conducted 4G base station tests in some cities, such as Shanghai, Nanjing, and Guangdong." But according to a report from investment bank Deutsche Bank, China Telecom's CDMA network is currently more compatible than China Unicom. The low WCDMA and China Mobile TD-SCDMA networks, coupled with the fact that China Telecom currently has fewer 3G base stations, has placed more burden on China Telecom to build 4G base stations.
China Telecom also understands this, so it intends to launch 4G services in phases starting this year. Because China Telecom has a good 3G coverage in urban areas and has its own advantages, 4G services are first popularized in key cities, and the number of 4G base stations deployed or deployed is similar to that of the other two operators.
The 4G system that China Telecom adopts in the end has not been clarified. Some media expect that China Telecom will obtain a TD-LTE license, because the country has asked TD-LTE to have three points in the world. At present, China Mobile has explicitly supported TD-LTE, while China Unicom supports LTE-FDD.
However, from the 4G trials that China Telecom has already started in key cities, it uses the trial network of LTE-FDD, and there are many equipment vendors involved, all of which provide base station equipment for free, and the test results are still satisfactory.
Based on this, industry insiders believe that China Telecom is unlikely to get a TD-LTE license. In addition, the move of many CDMA operators overseas to LTE-FDD will allow China Telecom to rethink its thinking. According to reports, within the two operators of China Telecom and China Unicom, the top-down consensus is that the best result is the construction of LTE-FDD, followed by TD-LTE and LTE-FDD hybrid networking, the worst The choice is to build TD-LTE. "The industrial maturity of LTE-FDD is more advanced than that of TD-LTE. There may be more stable networks and better terminals. It seems to have little effect, but it is critical and fatal in the market competition." A China Telecom employee Say.
Chang Xiaobing, chairman of China Unicom, also believes that different operators make different arrangements based on their own strategies, there is no need to require all operators to be a model. In fact, China Unicom's 3G license is a WCDMA license, which can be smoothly evolved to LTE-FDD. The best arrangement is to obtain an LTE-FDD license.
Equipment manufacturers leveraging the power
4G applications are heating up in the country. Ministry of Industry and Information Technology Minister Miao Wei recently revealed that 4G licenses are expected to be issued this year. Some industry executives and research institutions also made relevant predictions on the scale of investment in the telecom equipment market in 2013. The United States, Brazil, and China will lead the development of the global telecommunications industry.
China Mobile has established two “One Hundred†development goals for 2013. TD-LTE capital expenditures will increase significantly from RMB 5 billion in 2012 to RMB 28 billion, an increase of 4.6 times. At the same time, China Unicom and China Telecom are also secretly making efforts. If 4G is licensed in the second half of 2013, China Unicom and China Telecom will inevitably increase their investment in 4G.
All kinds of signs indicate that domestic 4G investment this year or exceeds expectations, and local telecom equipment vendors that have been “stopping†will suffer a series of setbacks overseas and will also be expected to share 4G “feast†at home to get rid of the current embarrassing situation.
Yi Yi Consulting CEO Zhang Yi said that at present, ZTE, Huawei and other veteran equipment vendors in the 2G, 3G market and other brand manufacturers in the competitive process, the advantages gradually diminished, "for the time being the operator is still the 'big money' Take the goods, but there is no profit." Therefore, these veteran equipment manufacturers urgently need to promote the 4G market to replace the existing market, "I am afraid that 4G is the territory of the terminal vendors competing for snatch, so we are actively preparing."
According to industry insiders, the overall capital expenditures of domestic operators are improving, and the steady growth of investment in TD-LTE and broadband transmission networks, among other things, will directly stimulate a new round of reshuffling in the telecommunications equipment market. For ZTE and Huawei, which have a relatively large market share in the domestic 3G, 4G and transmission network markets, this may be an important thrust for their development in 2013.
However, these veteran equipment manufacturers' eyes are not limited to the domestic market. Although there have been some setbacks in the international market, they are still leveraging their efforts to firmly deploy 4G. Huawei mentioned in its 2011 annual report that the company has deployed more than 150 SingleRAN commercial networks in the world and has already had the ability to support LTE. As of the end of 2011, Huawei's wireless network products and solutions have been used by more than 500 operators worldwide and have accumulated more than 2 million base stations. In addition to traditional operational commerce, Huawei has also experienced frequent declines in the terminal industry in recent years. Its high-end LTE smartphones have been recognized in markets such as Japan, the United States, and Europe, and have successfully established high-end brand images.
If the power of the grid is cut off, the grid-connected inverter needs to be disconnected from the grid quickly. This is a regulation of the National Electrical Code (NEC) in the United States to ensure that when the grid is out of power, the grid-connected inverter will not provide power to the grid, and at this time the workers who maintain the grid will not be electrocuted.
Properly configured, grid-tie inverters allow a home to use alternative energy sources that it generates itself (such as solar or wind power) without cumbersome wiring and without the need for batteries. If there is insufficient alternative energy, the insufficient part will still be provided by electricity from the grid.
Grid-connected inverters are widely used in household photovoltaic power generation systems, commercial and industrial photovoltaic power plants and other scenarios. By connecting to the grid, they help to achieve efficient use of renewable energy and reduce carbon emissions, promoting sustainable development and popularization of clean energy.